Nutritional Disorders
This presentation delves into the essential role of vitamins in human nutrition, covering classifications, sources, functions, and risk factors associated with deficiencies. Helpful insights into vitamin-related disorders and treatment strategies are discussed in detail.
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Presentation Transcript
Nutritional Disorders Vitamins and Minerals (The Micronutrients) Dr. Zainab A. Al-Mayyahi Department of Medicine College of Medicine University of Basrah
Objectives By the end of this lecture you should be able to Define Vitamins Classify vitamins Identify causes of vitamins deficiencies Describe the clinical features of vitamins deficiency and excess Treat vitamin related nutritional disorders 2 University of Basrah/College of Medicine/Department of Medicine
Vitamins are Biochemical substances that are required in human diet for optimal physiological functions. Both deficiency and excess of vitamins can cause disease. Vitamins deficiencies are most prevalent in developing countries but still present in developed countries. 3 University of Basrah/College of Medicine/Department of Medicine
Risk factors for vitamin deficiency Malnutrition. Older people. Growing children . Pregnancy. Drugs. Maldigestion Malabsorption. Alcoholics 4 University of Basrah/College of Medicine/Department of Medicine
Functions of Vitamins Vital roles in different physiological processes e.g. coenzymes. Some have pharmacological actions when given at supraphysiological doses e.g. Niacin and vitamin A. 5 University of Basrah/College of Medicine/Department of Medicine
Classifications of Vitamins Fat soluble vitamins A, D, K, E (DEKA) Water soluble vitamins C, B- complex group 6 University of Basrah/College of Medicine/Department of Medicine
Fat soluble vitamins (DEKA)
Vitamin A Sources : Animal source (Retinol): liver, fish, eggs. Plant sources (B-Carotene): dark greens and colored vegetables and fruits. Synthetic forms. Daily requirements: 1.5 mg= 5000 IU/day. 8 University of Basrah/College of Medicine/Department of Medicine
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Functions of vitamin A Night vision: retinaldehyde (retinal) is critical for rhodopsin in the rods of retina. Growth and cell differentiation: retinoic acid. Reproduction and embryogenesis. Humeral immunity. Hematopoiesis. Antioxidant: B-Carotene. Therapeutic role: acne , psoriasis, leukemia. 10 University of Basrah/College of Medicine/Department of Medicine
Vitamin A deficiency Vitamin A is one of the most common causes of blindness in children around the world. Causes of vitamin A deficiency: Famine and under-nutrition. Malabsorption Obstructive jaundice. Alcoholism. Drugs e.g. cholestyramine. 11 University of Basrah/College of Medicine/Department of Medicine
Clinical features of vitamin A deficiency Visual symptoms and signs: 1. Night blindness: impaired vision in dim light. 2. Xerophthalmia: dry lusterless cornea. 3. Bitot s spots : glistening white plaques of desquamated conjunctival epithelium firmly adherent to underlying conjunctiva. 4. Keratomalacia: thinning and ulceration of the cornea, scaring and total blindness. 12 University of Basrah/College of Medicine/Department of Medicine
Xerophthalmia 13 University of Basrah/College of Medicine/Department of Medicine
Bitots spots 14 University of Basrah/College of Medicine/Department of Medicine
Keratomalacia 15 University of Basrah/College of Medicine/Department of Medicine
Other features of vitamin A deficiency Increased susceptibility to infections. Hyperkeratosis of the skin, acne, dry hair Growth impairment in children Fatigue , insomnia Weight loss 16 University of Basrah/College of Medicine/Department of Medicine
Treatment of vitamin A deficiency Treatment of underlying cause if present. Encourage a vitamin A rich diet. Vitamin A (retinol) supplements (60 mg= 200,000 IU in form of retinyl palmitate repeated after 14 days then every six months. Eye surgeon referral if required. 17 University of Basrah/College of Medicine/Department of Medicine
Prevention of vitamin A deficiency Encourage vitamin A rich diet. Prophylactic oral dose of retinol 60 mg (200,000 IU) for pre-school children. Fortification of food with vitamin A. 18 University of Basrah/College of Medicine/Department of Medicine
Vitamin A toxicity Two forms : Carotenemia ; increased intake of B- Carotene Hypervitaminosis A ; increased intake of retinol 20 University of Basrah/College of Medicine/Department of Medicine
Carotenemia High level of B-Carotene is not toxic, it cause (Carotenemia) which is a yellow-orange discoloration of skin especially palms and soles but not sclera and this resolve after decreasing B- Carotene intake. This can also occur in cases of hypothyroidism (decreased metabolism of B- Carotene) 21 University of Basrah/College of Medicine/Department of Medicine
Retinol toxicity (hypervitaminosis A) - Two forms: Acute toxicity Chronic toxicity (hypervitaminosis A) 22 University of Basrah/College of Medicine/Department of Medicine
Vitamin A toxicity (acute) Acute toxicity: ingestion of a single dose of 100- 150 mg of retinol will lead to abdominal pain , headache, vertigo, diplopia, bulging fontanels in children, seizures, and exfoliative dermatitis. 23 University of Basrah/College of Medicine/Department of Medicine
Chronic vitamin A toxicity Chronic retinol toxicity occur if the daily intake is more than 15 mg=50,000 IU for more than three months. Symptoms include: dry fissured skin, hair loss, headache, nausea , vomiting ( Increase intra-cranial pressure) hepatomegaly and bone pain. 24 University of Basrah/College of Medicine/Department of Medicine
Vitamin A toxicity treatment Confirm diagnosis by measurement of level of vitamin A Treatment is symptomatic and supportive. 25 University of Basrah/College of Medicine/Department of Medicine
Vitamin A and pregnancy In high doses retinol is teratogenic Pregnant women should not receive more than 3 mg/d of vitamin A (10,000 IU) 26 University of Basrah/College of Medicine/Department of Medicine
